From: Ramkumar Ramachandra <artagnon@gmail.com>
Date: Thu, 20 Jun 2013 16:04:17 GMT
Subject: Re: [PATCH] pull: pull into void by fast-forwarding from empty tree
Message-ID: <CALkWK0k-SaYz2uCpeXnTTL7HvBQ=r1PhWCJeDvdpuKL6qhDoig@mail.gmail.com>
In-Reply-To: <45f6841746e5dcea03a97fc3ea24aef274728023.1371731513.git.trast@inf.ethz.ch>

Thomas Rast wrote:
> diff --git a/git-pull.sh b/git-pull.sh
> index 638aabb..1f84383 100755
> --- a/git-pull.sh
> +++ b/git-pull.sh
> @@ -266,10 +266,17 @@ case "$merge_head" in
>         ;;
>  esac
>
> +# Pulling into unborn branch: a shorthand for branching off
> +# FETCH_HEAD, for lazy typers.
>  if test -z "$orig_head"
>  then
>         git update-ref -m "initial pull" HEAD $merge_head "$curr_head" &&
> -       git read-tree -m -u HEAD || exit 1
> +       # Two-way merge: we claim the index is based on an empty tree,
> +       # and try to fast-forward to HEAD.  This ensures we will not
> +       # lose index/worktree changes that the user already made on
> +       # the unborn branch.
> +       empty_tree=4b825dc642cb6eb9a060e54bf8d69288fbee4904

Perhaps replace this magic with $(git hash-object -t tree /dev/null)
or $(git mktree </dev/null)?